Sökning: "Martensite"

Visar resultat 1 - 5 av 81 avhandlingar innehållade ordet Martensite.

  1. 1. Nucleation and growth of martensite in steel

    Författare :Annika Borgenstam; KTH; []
    Nyckelord :martensite; Fe-alloys; α-martensite; athermal martensite; isothermal martensite; plate martensite; lath martensite; nucleation; growth; thermodynamics; plateau temperature; driving force; activation energy; bainite; Widmanstätten α; diffusive mechanism; displacive mechanism; ε-martensite; TECHNOLOGY; TEKNIKVETENSKAP;

    Sammanfattning : .... LÄS MER

  3. 2. Modelling and Characterisation of the Martensite Formation in Low Alloyed Carbon Steels

    Författare :Jessica Gyhlesten Back; Lars-Erik Lindgren; Göran Engberg; Bevis Hutchinson; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Dilatometry; Hardness; EBSD; Martensite; Austenite; Kurdjumov-Sachs; Phase transformation; Modelling; Material Mechanics; Materialmekanik; Steel Forming and Surface Engineering;

    Sammanfattning : The current work contains experimental and theoretical work about the formation of martensite from the austenitic state of the steel Hardox 450. Simulation of rolling and subsequent quenching of martensitic steel plates requires a model that can account for previous deformation, current stresses and the temperature history, therefore dilatometry experiments were performed, with and without deformation. LÄS MER

  4. 3. Low Temperature Austenite Decomposition in Carbon Steels

    Författare :Albin Stormvinter; Annika Borgenstam; John Ågren; Peter Hedström; John G. Speer; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Carbon steels; Electron backscattered diffraction; Martensite; Microscopy; Microstructure; Thermodynamic modeling;

    Sammanfattning : Martensitic steels have become very important engineering materials in modern society. Crucial parts of everyday products are made of martensitic steels, from surgical needles and razor blades to car components and large-scale excavators. LÄS MER

  5. 4. Development of Structural Steels for Powder Bed Fusion - Laser Beam

    Författare :William Hearn; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; tensile properties; in situ tempering; process development; martensite; additive manufacturing; cold cracking; low-alloy steel; structural steel; powder bed fusion – laser beam; carbon steel;

    Sammanfattning : Over the past decade, powder bed fusion – laser beam (PBF-LB) has attracted noticeable attention from both academia and industry. However, there remains a scarcity of approved material for the process, as fewer than 40 alloys are commercially available. LÄS MER

  7. 5. Railway Wheel Flats. Martensite Formation, Residual Stresses, and Crack Propagation

    Författare :Johan Jergeus; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; sliding contact; metallographic investigation; crack propagation; thermal shock; constitutive modelling; phase transformations; railway wheel flats; full-scale field experiments; transformation plasticity; tread damage; residual stresses; spalling; martensite formation;

    Sammanfattning : A railway wheel flat is a flat spot on the rolling surface of a wheel caused by its unintentional sliding on the rail. The reason for the sliding may be poorly adjusted, frozen or defect brakes, or too high braking forces in relation to the available wheel/rail adhesion. LÄS MER